1628981 has 4 divisors (see below), whose sum is σ = 1635264. Its totient is φ = 1622700.

The previous prime is 1628947. The next prime is 1628983. The reversal of 1628981 is 1898261.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1898261 = 199 ⋅9539.

It is a cyclic number.

It is not a de Polignac number, because 1628981 - 2⁶ = 1628917 is a prime.

It is a super-2 number, since 2×1628981² = 5307158196722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1628983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2735 + ... + 3276.

It is an arithmetic number, because the mean of its divisors is an integer number (408816).

2^1628981 is an apocalyptic number.

It is an amenable number.

1628981 is a deficient number, since it is larger than the sum of its proper divisors (6283).

1628981 is an equidigital number, since it uses as much as digits as its factorization.

1628981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6282.

The product of its digits is 6912, while the sum is 35.

The square root of 1628981 is about 1276.3153998914. The cubic root of 1628981 is about 117.6626628960.

The spelling of 1628981 in words is "one million, six hundred twenty-eight thousand, nine hundred eighty-one".